Materials & grades
655M13 (EN36A) case-hardening steel: equivalents 15NiCr13 (1.5752), SNC815 and 13Ni13Cr3
655M13, formerly EN36A, is a UK case-hardening steel with about 3.25 % nickel and 0.8 % chromium, used for heavily loaded gears and shafts in large sections. Its European equivalent is 15NiCr13 (1.5752), formerly DIN 14NiCr14, and Japan's SNC815 is a close equivalent.
Names by standard
What it is called in each region
| Region | System | Designation | Standard | Match |
|---|---|---|---|---|
| USA | AISI/SAE | 3310Listed against EN36A by Smiths Metal Centres and Liberty Speciality Steels. 3310 has about 1.5 % chromium (1.40–1.75 %), double 655M13's. | — | Closest equivalent |
| AISI/SAE | 9310Listed with 3310 by the same suppliers, but 9310 has 1.00–1.40 % chromium and 0.08–0.15 % molybdenum. | SAE J404 | Closest equivalent | |
| UK | BS 970 | 655M13BS 970 has been withdrawn. | BS 970-3:1991 | Same material |
| BS 970 (1955 EN series) | EN36ASuperseded name for 655M13. | BS 970:1955 | Same material | |
| BS 970 | 832M13 (EN36C)Adds molybdenum; higher hardenability. | BS 970 (older parts; not in BS 970-3:1991) | Closest equivalent | |
| EU | EN 10027-1 name | 15NiCr13Carbon 0.14–0.20 %, nickel 3.00–3.50 %, chromium 0.60–0.90 %. | EN 10084:2008 | Equivalent |
| EN 10027-2 number | 1.5752Material number of 15NiCr13. | EN 10084 | Equivalent | |
| DIN (legacy) | 14NiCr14Superseded German name for 1.5752, quoted against EN36A by UK and Australian suppliers. | — | Equivalent | |
| India | IS 4432 | 13Ni13Cr3Carbon 0.10–0.15 %, nickel 3.00–3.50 %, chromium 0.60–1.00 %. | IS 4432:1988 | Closest equivalent |
| Japan | JIS G 4053 | SNC815Carbon 0.12–0.18 %, nickel 3.00–3.50 %, chromium 0.60–1.00 %. | JIS G 4053 | Equivalent |
| JIS G 4052 | SNC815HHardenability-guaranteed version of SNC815. | JIS G 4052 | Closest equivalent |
On equivalence
- 655M13 (BS 970-3:1991) replaced EN36A (BS 970:1955). They are the same steel under two naming systems, so both are listed as the same here.
- UK sources disagree on the composition. Interlloy and Vulcan tabulate 0.10–0.16 % carbon and 0.70–1.00 % chromium for 655M13. Liberty Speciality Steels and Smiths Metal Centres quote 0.12–0.18 % carbon and 0.60–1.10 % chromium for EN36, the older analysis. Check the mill certificate.
- 15NiCr13 (1.5752), formerly DIN 14NiCr14, is a close equivalent. It has more carbon (0.14–0.20 %) than the voestalpine figure for 655M13 and 0.60–0.90 % chromium.
- SAE 3310 and 9310 are often listed beside EN36A but neither matches it. 3310 has about 1.5 % chromium and 9310 has 1.00–1.40 % chromium and added molybdenum. Treat both as closest.
- EN36C (832M13) is the molybdenum-bearing sibling with higher hardenability. It is the UK grade nearer 9310. See the 9310 page.
- IS 4432 grade 13Ni13Cr3 has about the same nickel and chromium as 655M13 but a lower carbon range (0.10–0.15 %). Japan's SNC815 is a close match with 0.12–0.18 % carbon.
- The 655M13 sulphur limit here (≤0.040 %) is the figure Interlloy and Vulcan print. A third-party copy of a BS 970-3 table note gives a general limit of sulphur ≤0.050 % and phosphorus ≤0.040 % for alloy case-hardening grades. Check the mill certificate.
Chemical composition
Composition limits, mass %
| Element | 9310 (comparison)USA · SAE J404 (as tabulated by MakeItFrom) | 655M13UK · BS 970-3:1991 (as tabulated by Interlloy and Vulcan) | EN36 (655M13)UK · As quoted by Liberty Speciality Steels and Smiths Metal Centres | 15NiCr13 (1.5752)EU · EN 10084 | 13Ni13Cr3India · IS 4432:1988 | SNC815Japan · JIS G 4053 |
|---|---|---|---|---|---|---|
| C | 0.08–0.13 | 0.10–0.16 | 0.12–0.18 | 0.14–0.20 | 0.10–0.15 | 0.12–0.18 |
| Si | — | 0.10–0.40 | 0.10–0.35 | ≤0.40 | 0.15–0.35 | 0.15–0.35 |
| Mn | 0.45–0.65 | 0.35–0.60 | 0.30–0.60 | 0.40–0.70 | 0.40–0.70 | 0.35–0.65 |
| P | — | ≤0.040 | ≤0.050 | ≤0.025 | ≤0.035 | ≤0.030 |
| S | — | ≤0.040 | ≤0.050 | ≤0.035 | ≤0.035 | ≤0.030 |
| Cr | 1.00–1.40 | 0.70–1.00 | 0.60–1.10 | 0.60–0.90 | 0.60–1.00 | 0.60–1.00 |
| Ni | 3.00–3.50 | 3.00–3.75 | 3.00–3.75 | 3.00–3.50 | 3.00–3.50 | 3.00–3.50 |
| Mo | 0.08–0.15 | — | — | — | — | — |
Mechanical properties
Strength and hardness
| Condition | Tensile strength | Yield strength | Elongation | Hardness |
|---|---|---|---|---|
| Annealed, typicalTypical values, not minimums; maximum 255 HB as suppliedEN36A supplier data sheet | 700–770 MPa102–112 ksi | 540 MPa78 ksi | 25 (5.65√S0) % | 212 HB typical |
| As supplied to BS 970-3:1991 (655M13), blank carburized19 mm test bar; specified minimums; Izod ≥40 J, Charpy ≥35 JEN36A supplier data sheet citing BS 970-3:1991 | ≥1000 MPa≥145 ksi | — | ≥9 % | — |
| Blank case hardened, typical19 mm test piece; typical values; Izod 40 J, reduction of area 50 %Liberty Speciality Steels; Smiths Metal Centres | 1100 MPa160 ksi | — | 15 % | 341 HB |
| Core after carburizing, 11 mm sectionAs published by voestalpine (listed for 9310 / 1.5752 / EN36A)voestalpine HPM data sheet | 980–1280 MPa142–186 ksi | 785 MPa114 ksi | 8 % | — |
| Core after carburizing, 30 mm sectionAs published by voestalpine (listed for 9310 / 1.5752 / EN36A)voestalpine HPM data sheet | 880–1180 MPa128–171 ksi | 765 MPa111 ksi | 9 % | — |
| Core after carburizing, 63 mm sectionAs published by voestalpine (listed for 9310 / 1.5752 / EN36A)voestalpine HPM data sheet | 780–1080 MPa113–157 ksi | 635 MPa92 ksi | 10 % | — |
| Oil quenched from 830 °C, tempered at 200 °CTypical values, 50 mm section; Izod 95 JEN36A supplier data sheet | 1140 MPa165 ksi | 896 MPa130 ksi | 20 % | 340 HB |
| Core of case-hardened test bar (13Ni13Cr3)16 mm diameter; tensile range, yield and elongation minimums; elongation on 5.65√A gaugeIS 4432:1988, Table 4 | 1000–1300 MPa145–189 ksi | ≥720 MPa≥104 ksi | ≥8 % | — |
| Core of case-hardened test bar (13Ni13Cr3)30 mm diameter; tensile range, yield and elongation minimumsIS 4432:1988, Table 4 | 900–1250 MPa131–181 ksi | ≥650 MPa≥94 ksi | ≥9 % | — |
| Core of case-hardened test bar (13Ni13Cr3)63 mm diameter; tensile range, yield and elongation minimumsIS 4432:1988, Table 4 | 850–1200 MPa123–174 ksi | ≥600 MPa≥87 ksi | ≥10 % | — |
In practice
Behaviour, heat treatment and uses
Characteristics
- A 3.2 % nickel-chromium case-hardening steel with high hardenability: high core strength, toughness and fatigue resistance in relatively large sections, with case hardness up to about 62 HRC (supplier data sheet).
- Can also be used uncarburized, hardened and tempered, as a high-tensile steel.
- Does not respond to flame or induction hardening because of its low carbon content.
- Hardened and tempered (uncarburized) it can be nitrided at about 490–530 °C to about 60 HRC. The high nickel lowers case hardness or lengthens the cycle compared with other alloy grades (supplier data sheet).
- Very good machinability in the annealed condition and readily weldable in the annealed supplied condition (Smiths Metal Centres).
Heat treatment
- Forging: heat to about 1150 °C and do not forge below about 850 °C; cool slowly (supplier data sheet).
- Annealing: about 830–850 °C, furnace cool; voestalpine gives 650–700 °C with slow cooling.
- Normalizing: about 880–920 °C, cool in still air, then temper at 650–660 °C for better machinability; voestalpine gives 850–880 °C.
- Carburizing: about 900–950 °C (supplier data sheet); voestalpine gives 880–950 °C; IS 4432 gives 890–940 °C for 13Ni13Cr3.
- Core refining: reheat to about 830–880 °C and oil quench, water quench or air cool (supplier data sheet); IS 4432 gives 860–880 °C.
- Case hardening: reheat to about 760–800 °C and oil quench, then temper immediately (supplier data sheet); IS 4432 gives 790–830 °C.
- Tempering: about 150–200 °C, 1–2 hours per 25 mm of section (supplier data sheet).
- Stress relieving: about 600–650 °C, 1 hour per 25 mm, cool in still air (supplier data sheet).
Impieghi tipici
- Heavy-duty gears and ring gears
- Crankshafts and connecting rods
- Shafts, couplings and king pins
- Heavy-duty bushings, collets and conveyor pins
- Sprockets
Alloy and case-hardening steels
Similar grades compared
| Classe | C % | Mn % | Cr % | Ni % | Tensile, first listed condition |
|---|---|---|---|---|---|
| 655M13 / EN36A | 0.08–0.13 | 0.45–0.65 | 1.00–1.40 | 3.00–3.50 | 700–770 MPa |
| 16MnCr5 | 0.13–0.18 | 0.70–0.90 | 0.70–0.90 | ≤0.25 | ≥1000 MPa |
| 20MnCr5 | 0.17–0.22 | 0.70–0.90 | 0.70–0.90 | ≤0.25 | ≥1200 MPa |
| 8620 / 20NiCrMo2-2 | 0.18–0.23 | 0.70–0.90 | 0.40–0.60 | 0.40–0.70 | 530 MPa |
| 9310 | 0.08–0.13 | 0.45–0.65 | 1.00–1.40 | 3.00–3.50 | 1289 MPa |
| 4130 / 25CrMo4 | 0.28–0.33 | 0.40–0.60 | 0.80–1.10 | ≤0.25 | 590–760 MPa |
| 4135 / 34CrMo4 | 0.33–0.38 | 0.70–0.90 | 0.80–1.10 | ≤0.25 | 1000–1200 MPa |
| 4140 / 42CrMo4 | 0.38–0.43 | 0.75–1.00 | 0.80–1.10 | ≤0.25 | 655 MPa |
| 4340 / EN24 | 0.38–0.43 | 0.60–0.80 | 0.70–0.90 | 1.65–2.00 | 745 MPa |
| 5140 / 41Cr4 | 0.38–0.43 | 0.70–0.90 | 0.70–0.90 | ≤0.25 | 570 MPa |
Composition from the US standard where one exists, otherwise the first standard listed on each grade's page. Strength conditions differ between grades; open a grade for its full table.
Domande e risposte
Common questions
What is the equivalent of EN36A?
655M13 is the current BS 970 name. The EN equivalent is 15NiCr13 (1.5752), formerly DIN 14NiCr14, and the Japanese equivalent is SNC815. India lists 13Ni13Cr3 in IS 4432 as the closest.
Is EN36 the same as 9310?
No. EN36A (655M13) has no molybdenum and 0.70–1.00 % chromium, while 9310 has 1.00–1.40 % chromium and 0.08–0.15 % molybdenum. Some suppliers list them together, but they are not interchangeable for critical work.
What is the difference between EN36A and EN36C?
EN36C (832M13) adds molybdenum to the 3 % nickel-chromium base of EN36A (655M13). The molybdenum raises hardenability and core strength.
Is EN36 weldable?
Smiths Metal Centres describes it as readily weldable in the annealed supplied condition. Weld before carburizing and heat treat afterwards.
What is EN36A used for?
Heavily loaded carburized parts in large sections: gears, ring gears, shafts, king pins, heavy-duty bushings, sprockets and crankshafts.
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Related references
References
Sources
- IS 4432:1988 Case hardening steels (public copy) — Grades, composition (Table 1), core properties of case-hardened test bars (Table 4) and heat-treatment guidance.
- Kobelco: wire rod and bar standard tables (JIS G 4053 alloy steels for machine structure) — JIS G 4053 composition tables (2008 revision).
- voestalpine High Performance Metals: AISI 9310 / 1.5752 / EN36A data sheet (2026) — Typical analysis, heat treatment, annealed hardness and carburized core properties.
- EN36A case hardening steel supplier data sheet (BS 970 655M13, W.Nr 1.5752) — Composition, BS 970-3 test requirements, typical properties and detailed heat treatment.
- Liberty Speciality Steels: EN36 (655M13) data sheet — EN36 analysis and typical blank-hardened properties; lists 1.5752 and SAE 3310 / 9310.
- Smiths Metal Centres: EN36 technical data sheet — Related specifications, composition, weldability and machinability.
- AUSA: case hardening steel 15NiCr13 — 15NiCr13 composition per EN 10084 and equivalents (DIN 14NiCr14, 1.5752).
- SteelNumber: 15NiCr13 / 1.5752 — EN 10084 composition and supply hardness; lists BS 655M13.
- Textron Steel Alloys: EN36C / 832M13 — 832M13 composition and note that it adds molybdenum.
- Total Materia: SAE 3310 — 3310 chromium limits.
- MakeItFrom: SAE-AISI 9310 (1.6657, G93106) Ni-Cr-Mo steel — SAE 9310 composition limits used for comparison.
- Vulcan Engineering Steels: case hardening steels (EN36A) — 655M13 composition as tabulated for BS 970-3:1991 (phosphorus and sulphur 0.04 % max).
Values summarize published limits and typical data. The governing standard and the current edition control; check them before specifying.
